1. Field of the Invention
This invention relates to an endoscope of the waterproof type.
2. Prior Art
Waterproof endoscopes comprises an insertion tube made of a relatively flexible material and has a free end adapted to be inserted into a hollow organ of a subject. Such a waterproof endoscope is entirely hermetically sealed, and is subjected to a sterilization at elevated temperatures in an atmosphere of ethylene oxide or the like. During this high temperature sterilization, the flexible insertion tube becomes softened due to the high temperature encountered, and the pressure in the endoscope is so increased that the flexible insertion tube is expanded or bulged and may finally be subjected to rupture.